Oil-switch



1 G. A. BURNHAM.

OIL SWITCH.

APPLICATION FILED MAY 26. 1911.

Patented Dec. 6, 1921.

UNITED STATES PATENT OFFICE.

GEORGE A. BURNHAM, GUS, IVI.A.SS.LCI{USETTS; ASSIGNOP, 'I'O SEARS B. CONDIT, JR., 0? BRGOKLIIQ'E, MASSACHUSETTS.

OIL-SWITCH.

Application filed May 26, 1917.

To alt whom it may concern:

Be it known that I, Gnonon BUPNHAEI, a citizen of the United States. res 22 at c" .L w r o J c-augus, 1n the county of itssex and state or Massachusetts, have invented an improvement in Oil-Switches, of which the following is a specification.

My invention relates to electric switches, and has specific reference to deal switches employed for the control induc tion motors, and in which the contacts are made and broken under oil is intended as an improvement on the electric switch shown in my application Patent No. 1,312,- 777, dated Aug. 12, 1919.

An object of my invention is provide a switch of the type specified with trip coils and with latch mechanism so associated with the movable members and operating handle that when the switch handle has been moved to its running position, the latch mechanism tends to maintain the hand id the movable switch member in this position until actuated, because of an excess current flow in the trip coils, to operatively disconnect the handle and movable switch member, whereupon the switch member moves to open position and the handle independently moves to neutral position; that will permit the switch member to move to open position upon efiective energization of the trip coils even though the operating handle is manually maintained in the running position; and that will permit the switch member to be moved to open position by the manual movement of the switch handle to neutral position.

A further object of my invention is provide means whereby the switch is no; mall'y maintained in a neutral position against movement in one direction, and whereby the switch must be moved into the starting position and then must be rapidly moved into the running position.

A further object oi my invention is to provide a switch that is cheap and durable in construction and reliable in operation.

Certain teaturesherein set forth and illustrated are also disclosed in my co-penoing application Serial No. 169,227, filed May 17, 1917.

Figure 1 is an elevation, partly in section,

of a switch embodying my invention.

Specification of Letters Patent.

Patented Dec. 6, 1921.

Serial No. 171,274.

Fig. 2 is an elevation of the switch operating mechanism.

Fig. 3 is a plan view of the switch operating mechanism.

ig. 4 is a detail, in elevation, of the switch operating handle and latch.

is here shown, the switch in which my invention is incorporated is similar to that shown in my said application Patent No. 1,312,777, dated Aug. 12, 1919, comprises a base 10 of slate or other insulating material, which is secured between a lower tank or receptacle 11, adapted to contain oil and to inclose the stationary and movable switch contacts, and an upper casing 12 which incloses the switch operating mechanism. The tank 11, casing 12 and bas 10 are clamped secured together by means of wing bolts 13, fastened to tank 11, and engaging lugs on casing 12. A cover 14 incloses the top of casing 12 and is secured thereto by screws.

Movable switch members, consisting of a plurality of flexible spring strips 15, terminating in detachable contact members 16, depend from base 10 into the oil of container 11, and are secured to said base 10 by bolts 17, and a plurality of stationary contact members 18 and 19 also depend into the 1. l of container 11 and terminate in detachable contacts 20 and 21, equally disposed on each side oi the normal or open circuit position of the movable switch members. Contact members 18, 19 are secured to base 10 by bolts 22 and 23.

Spring strips 15 are secured intermediate the lengths tiereoii between two bars of insulating material 24- which are clamped or rastened together by screws 25 which also serve to secure a metal plate 26 to the top bar Metal plate 26 has an car 27 provided with a perforation in which the hooked end 28 of the switch operating rod 29 is inserted. Operating rod 29 extends through an opening 31 in base 10 and the vertical movement of said rod is employed to move the clamp formed of bars 24 and flex the strip 15 and thus move the contact members 16 secured thereto into engagement with one or the other of the stationary contacts 20 and 21.

Rod 29 is a component part of the operating means for the switch, and as here shown, hasits upper end provided with an eye 30 which receives the crank portion 32 of a shaft. 33Varranged horizontally in the top casin 12 and'adapted to oscillate in bean ings 34 arranged in opposite side walls of casing 12. v s

A spring 35 is arranged on the rod 29,'between the eye 30 and the base 10, which is normally inert, but which is compressed by a downward movement or the rod. The lower end of spring 35 rests on a cover plate 36 for the hole 31 in base 10, and the rod 'extends through a hole in said cover plate,

a function of the spring 35 being to maintain said cover plate inposition von said base over said hole 311 l-ls the rod 29 moved in a vertical idirection-itis also laterally displaced in a slight amount in the hole 31 and Consequently, tae coverplate will follow'the movements ofthe rod but in all positions will completely cover the hole and thus prevent access of oil and oil vapor'to the upper chamber.

Shaft 33 is provided with a second crank 37, a-ngularly' displaced from the crank 32 and a link 38 is pivoted to said second crank 3?. Link 38 comprises one member of a toggleof which the second member is an arm 39 secured to a shaft 40 which has a bearing at 41 in a wall of the top casing 12 and has an operating handle 42 secured to its outer end and the straightening of which toggle serves to maintain. the switch inits closed position.

Link38 is provided with a slot 43 which has a recessed portion or notch 44. rlrm39 carries, at its extremity a pin 45, which, in

an operative position or" the switch, is in en.

gagement with notch 440i link 38.

A latch 46,. pivoted at to link 38 and )TOVlClGCl with an armr48 and a bent portion l J.

49 adapted to be engaged by the pin of the trip coils to cause the opening of the switch under overload, has a secon arm 50 disposedunder pinu of arm 39 and normally serves to maintain said pin in the notch 44 of link 38, whereby a movement of said arm 39 may be transmitted throngh link 38 to the shaft 33 to operate the movable switch members, and arm is provided with a curved face 51 conforming to the surtce ct pin 45 for the secure engagement of arm 50 with pin 45.

, Link 38 has an extension 54 terminating in a bent projection 52 against which the arm 48 of latch 46 is adapted to rest to limit movement. of the latch in one direction, 7

Gperating handle 42is secured to shaft 40 in an angular relation, with the arm 39 inoperative connection with link 38iand has its movement limited between two stops or pins 55 securedin the wall of the casing 12.

In the normal, "oropen position of the switch, the handle 42 hangs vertically downward in itsneutral position and the arm 39' andlink- 38 occupy the relative positions secured thereto by bolts 5 causes a movement or" the movable Contact, I

members 16 int contact with the stationary or starting contact members 20.. After the motor has acquired its normal speed, the switch handle 42 is moved to the opposite or running position, and pin 45 is maintained in notch 44 by latch 46, the move ment of arm 39 is transmitted through 38 to crank shaft 33 which is rotated, and switch contacts 16 are brought into contact with the stationary running contacts 21.

In the extreme or running position of the switch, the toggle formed of links 38 and arm 39 is slightly offset, being maintained in such position by the compression or": spring 35, and preventedagainst movement to further offset position by the engagementor" handle 42 with pin 55. 1

Upon the oocurrence'of a sui'iicient overload, the pin 56 is actuated bysufficient energization 01" the trip coils-hereinafter described, and operates to strike the bent portion 49 of latch 46 and impartan angular movement to saidlatch which serves to swing arm 50 from engagement with pin 45 of arm 39 suflicient to cause its disengage? ment with pin 45, whereupon, the restraint being removed from spring35 and contacts in notch 44, and notch 44 and the curved 'face 51 of arm 50 of latch 46 serve as a pivotal bearing for pin 45.

A frame 57 depending 7 supports the solenoids or trip coils 58, which are independently connected in series with two'of the stationary contact members. The solecores 58 operate in tubes 59 and said tubes are provided with vertical slots 59 through which project pins 60 which are a daptedfto"engage with the flange 61 of trip pin 56'upon'suflic1ent energization of said trip coils to move said pin intovengagement from base '10 and i fastened to the said cores 58 Saidpins are 4 with the latch 46, wherebyto trip said latch and cause the movement of the switch to open position. 1 a g I Tubes 59 are provided at their lower eX- treniities with spring sleeves .or collars 62,

adapted to be clamped to said tubes by bolts 3, and are adjustable longitudinally upon said tubes, and, by engagement with. of the cores or" trip coils 58, may v the position of said cores in said coils, 1 ml thereby vary the point at which said cores will be effectively energized to trip the latch, Themeans whereby I normally maintain the switch in normal neutral position nst a movement of the switch to running p: tion without first moving the switch to start ing position comprises a curved latch (3%, pivoted at to the wall of the casing 12 adjacent handle 42 and in the path of move ment of a pin 66 in said handle. The lower of latch 64 is provided with a notch face 6: or depression 68 that normally engages pin. (36 or handle 42, and normally prevents movement of said handle to the running poside of said sition of the switch. The arrangement of said notch 68 is such, however, that a move mentor" the switch handle to starting position is permitted. If the switch handle be now rapidly moved to the running position, the component of downward velocity of the pin 66 of handle 42 is greater than that of the notch 68 in said latch, falling under. the influence of gravity and consequently the pin 66 passes beyond the notch before the latch has fallen sufliciently to admit of effective engagementof the notch 68 with pin 66, and conscque itly the switch is permitted to move into its running position.

I claim p 1. An electric switch including a base, a receptacleadapted to contain oil secured to said base. flexible springstrips secured to said l e and depending therefrom into the oil in saidcontainer and terminating in detachable contact members, said spring strips and contact members constituting movable itch members, two sets of stationary si" in itch members secured to and depending 1:, w 1 1 1, iiom said base, detachable contacts thereon disposed in vertical position on each movable switch 'members, means including a crank switch-ooeratin shaft, p coil secured to and depending from i base rate the oil of said recep V in operating handle, toggle mechanism connecting said operating handle with said crank shaft, a latch associated with said toggle mechanism, said toggle mechanism and latch being so arrangedtha-t the switch members can be moved to open position upon eiiective energization of said trip coils with the operating handle manually maintained in running position, and that will permit a movement of said handle from running position to move said switch members from running position, and means associated with said handle whereby said handle is normally maintained in neutral position against a movement to running position, and whereby the operator is compelled to move said handle to starting position and then rapidly move it into running position.

2. An electric switch including movable switch members, two sets of stationary switch members, operating means for said movable members including a crank shaft, an operating handle, members comprising toggle mechanism connecting said handle with said crank shaft, said members adapted to be operably disconnected, a latch associated with one member of said toggle mechanism adapted to hold said members 0 erably connected, a trip coil associa-tec with a stationary contact and adapted to move said latch upon eilective energizz ion of said coil to operably disconnect said toggle members, said latch and toggle mechanism be ing so arranged as to permit the movementof said handle in one position to move said movable switch members to contact with one set of stationary switch members, to permit the movement of said handle to a second position to move said movable switch member into contact with said second set of stationary switch members, to permit a movement of said handle from said second position to move said movable switch men hers from their corresponding position and to permit the independent movement of said movable switch members from said second position to a neutral position upon suiiicient energization of said trip coil, regardless of the maintenance of said handle in said second position, and a latch forcompelling a movement of said handle to said first position previous to its compelled rapid movement to said second position.

3. An electric switch including two sets of stationary switch members, movable switch members, switch operating means, an operating handle, toggle mechanism connecting said switch operating means and said handle, latch pivoted to one of said toggle links and adapted for normal engagement with a component partof the other toggle link, whereby the two links are maintained in normal effective engagement, and means operable by a predetermined current flow to disengage said latch from the component part o1 said toggle link cause relative movement between the toggle links, whereby said toggle will be broken and the movable switch members moved to neutral disengaged position.

4. An electric switch including two sets of stationary switch members, movable switch members, switch operating means, an operating handle, members comprising toggle mechanism connecting said switch operating means and said handle, said members adapted to be operably disconnected, a latch pivoted to one of said toggle links and adapted to engage a, component part of the other toggle link, whereby the two links are maintained in normal. efi'ective engagement, and

means operable by, a predetermined current flow, to disengage said latch from the component part of said'tcggle link and cause a relative 'movement' between the toggle links,

whereby said toggle will be broken and permit the independent movement of the movswitch handle to actuate the movable switchmembers into engagement with one set of stationary switch members and a subsequent movement of the handle to move the movable switch members: into engagement with the second set of stationary members and to maintain said switch members in the latter position, and means operable upon a predetermined current flow to cause the disengagement of said'latch with the component part oi one of the toggle members, whereupon the toggle will bebroken to permit the movement of the mo'vableswitch members to neu- V tral disengaging position.

6. Anelectric switch including two sets of stationary switch members, movable switch )m'embers, rocking means adapted to be operated in either direction from a neutral position to cause said movable switch members toengage one or the other set of stationary contact members, an operating handle adapted to be actuated to operate the rocking means, an arm carriedby said handle, a pin on said arm, a link connected to said rocking means and having a slot in which the pin on said arm operates, said link andarm forming mechanism by means of which a move ment' of the'operating handle in one direction serves to. actuate the movable. switch members into contact, with one set of stationaryswitch members, and'said link and arm forminga toggle that serves to lockthe movable switchmembers into engagement with the other set, of stationary contacts upon movement or" the operating handle in the opposite direction, said pininsaid'arm fitting ,into a recess in the slot-of said link in the secondposition of the movable switch members,

- a latch pivoted to said link and having an arm normally tending to maintain said pin in the recess oi the slotand adapted to be moved from engagement with said pin'upon v a predetermined current flow, whereby said toggle will be broken and said. movable switch members moved to disengaged position. p V s 7, An electric switch comprising stationary and movable switch members, operating mechanism comprising an operating handle, members forming toggle mechanism connecting said handle and movable switch members, said toggle members adapted to be operably disconnected for the tripping of I V the switch, a latch arranged toinormally hold said members in operative condition,

and electrically controlled means'to' operate saidlatch andoperably disconnect said t0ggle members. V

8. An electric switch having starting, running, and neutral positions, an operating handle, operating mechanism arranged to be normally disconnected from said handle and to connect therewith only upon movement of said handle from neutral to starting positions, and electrically-controlled, means to disconnect said mechanism and handle to 7 cause the switch to move from running to neutral positions. r r 1 9. A double throw electric switch comprising movable and two sets of stationary switch members, an operating handle and switch operating mechanism arrangedto be operatively connected with said handleonly upona movement 'tllGIQOf from neutralto 7' starting position, and thereafter connected for movement from starting to running posinism from the handle to permit the switch to open.

' In testimony whereof, I have signed my tion, and electrically controlled means to .operatlvely disconnect the operating mechaname to this specification, in the presence of two subscribing witnesses. 7 V

GEORGE A. BURNHAM.

I V Witnesses T. T; GREENWOOD, H. B. DAVIS. 

